caa a22 4500 60551707X CHVBK 20210128100717.0 cr unu---uuuuu 210128e20150401xx s 000 0 eng 10.1007/s10533-015-0077-4 doi (NATIONALLICENCE)springer-10.1007/s10533-015-0077-4 Hydrological transitions drive dissolved organic matter quantity and composition in a temporary Mediterranean stream [Elektronische Daten] [Daniel von Schiller, Daniel Graeber, Miquel Ribot, Xisca Timoner, Vicenç Acuña, Eugènia Martí, Sergi Sabater, Klement Tockner] The implications of stream flow intermittency for dissolved organic matter (DOM) are not well understood despite its potential significance for water quality and ecosystem integrity. We combined intensive sampling with liquid chromatography and spectroscopic techniques to follow changes in DOC and DON concentrations as well as in DOM size fractions and spectroscopic properties in a temporary stream during an entire contraction-fragmentation-expansion hydrological cycle. DOC and DON concentrations remained low (range=1.4-5.2mgCL−1 and 0.05-0.15mgNL−1) during hydrological contraction and fragmentation, with concomitant increases in the proportion of high molecular weight substances (HMWS) during contraction and of DOM aromaticity during fragmentation. DOC and DON concentrations abruptly increased (up to 8.8mgCL−1 and 0.37mgNL−1) at the end of the fragmentation phase, with a concomitant increase in the non-humic, microbial and aquatic character of DOM. Upon rewetting, the DOC and DON concentrations reached their highest values (up to 12.7mg CL−1 and 0.39mgNL−1), with concomitant increases in the proportion of HMWS and in the humic, aromatic and terrestrial character of DOM. Subsequently, DOC and DON concentrations recovered to values similar to those at the contraction phase, while DOM composition variables indicated the prevalence of a DOM of humic and terrestrial character during the whole expansion phase. Overall, our results emphasize the importance of hydrological transitions for DOM dynamics in temporary streams, and point to the potential response of perennial streams under future water scarcity scenarios. Springer International Publishing Switzerland, 2015 Drying nationallicence Rewetting nationallicence Dissolved organic matter nationallicence Dissolved organic carbon nationallicence Temporary stream nationallicence Drought nationallicence von Schiller Daniel Catalan Institute for Water Research, Emili Grahit 101, 17003, Girona, Spain aut Graeber Daniel Department of Bioscience, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark aut Ribot Miquel Integrative Freshwater Ecology Group, Centre for Advanced Studies of Blanes (CEAB-CSIC), Accés a la Cala St. Francesc 14, 17300, Blanes, Spain aut Timoner Xisca Catalan Institute for Water Research, Emili Grahit 101, 17003, Girona, Spain aut Acuña Vicenç Catalan Institute for Water Research, Emili Grahit 101, 17003, Girona, Spain aut Martí Eugènia Integrative Freshwater Ecology Group, Centre for Advanced Studies of Blanes (CEAB-CSIC), Accés a la Cala St. Francesc 14, 17300, Blanes, Spain aut Sabater Sergi Catalan Institute for Water Research, Emili Grahit 101, 17003, Girona, Spain aut Tockner Klement Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 301, 12587, Berlin, Germany aut Biogeochemistry Springer International Publishing 123/3(2015-04-01), 429-446 0168-2563 123:3<429 2015 123 10533 https://doi.org/10.1007/s10533-015-0077-4 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10533-015-0077-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- von Schiller Daniel Catalan Institute for Water Research, Emili Grahit 101, 17003, Girona, Spain aut NATIONALLICENCE 700 1- Graeber Daniel Department of Bioscience, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark aut NATIONALLICENCE 700 1- Ribot Miquel Integrative Freshwater Ecology Group, Centre for Advanced Studies of Blanes (CEAB-CSIC), Accés a la Cala St. Francesc 14, 17300, Blanes, Spain aut NATIONALLICENCE 700 1- Timoner Xisca Catalan Institute for Water Research, Emili Grahit 101, 17003, Girona, Spain aut NATIONALLICENCE 700 1- Acuña Vicenç Catalan Institute for Water Research, Emili Grahit 101, 17003, Girona, Spain aut NATIONALLICENCE 700 1- Martí Eugènia Integrative Freshwater Ecology Group, Centre for Advanced Studies of Blanes (CEAB-CSIC), Accés a la Cala St. Francesc 14, 17300, Blanes, Spain aut NATIONALLICENCE 700 1- Sabater Sergi Catalan Institute for Water Research, Emili Grahit 101, 17003, Girona, Spain aut NATIONALLICENCE 700 1- Tockner Klement Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 301, 12587, Berlin, Germany aut NATIONALLICENCE 773 0- Biogeochemistry Springer International Publishing 123/3(2015-04-01), 429-446 0168-2563 123:3<429 2015 123 10533